githaven/modules/git/repo_base_nogogit.go
KN4CK3R f74c869221
Prevent double use of git cat-file session. (#29298)
Fixes the reason why #29101 is hard to replicate.
Related #29297

Create a repo with a file with minimum size 4097 bytes (I use 10000) and
execute the following code:
```go
gitRepo, err := gitrepo.OpenRepository(db.DefaultContext, <repo>)
assert.NoError(t, err)

commit, err := gitRepo.GetCommit(<sha>)
assert.NoError(t, err)

entry, err := commit.GetTreeEntryByPath(<file>)
assert.NoError(t, err)

b := entry.Blob()

// Create a reader
r, err := b.DataAsync()
assert.NoError(t, err)
defer r.Close()

// Create a second reader
r2, err := b.DataAsync()
assert.NoError(t, err) // Should be no error but is ErrNotExist
defer r2.Close()
```

The problem is the check in `CatFileBatch`:

79217ea63c/modules/git/repo_base_nogogit.go (L81-L87)
`Buffered() > 0` is used to check if there is a "operation" in progress
at the moment. This is a problem because we can't control the internal
buffer in the `bufio.Reader`. The code above demonstrates a sequence
which initiates an operation for which the code thinks there is no
active processing. The second call to `DataAsync()` therefore reuses the
existing instances instead of creating a new batch reader.
2024-02-21 19:54:17 +01:00

128 lines
3.2 KiB
Go

// Copyright 2015 The Gogs Authors. All rights reserved.
// Copyright 2017 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
//go:build !gogit
package git
import (
"bufio"
"context"
"errors"
"path/filepath"
"code.gitea.io/gitea/modules/log"
)
func init() {
isGogit = false
}
// Repository represents a Git repository.
type Repository struct {
Path string
tagCache *ObjectCache
gpgSettings *GPGSettings
batchInUse bool
batchCancel context.CancelFunc
batchReader *bufio.Reader
batchWriter WriteCloserError
checkInUse bool
checkCancel context.CancelFunc
checkReader *bufio.Reader
checkWriter WriteCloserError
Ctx context.Context
LastCommitCache *LastCommitCache
objectFormat ObjectFormat
}
// openRepositoryWithDefaultContext opens the repository at the given path with DefaultContext.
func openRepositoryWithDefaultContext(repoPath string) (*Repository, error) {
return OpenRepository(DefaultContext, repoPath)
}
// OpenRepository opens the repository at the given path with the provided context.
func OpenRepository(ctx context.Context, repoPath string) (*Repository, error) {
repoPath, err := filepath.Abs(repoPath)
if err != nil {
return nil, err
} else if !isDir(repoPath) {
return nil, errors.New("no such file or directory")
}
// Now because of some insanity with git cat-file not immediately failing if not run in a valid git directory we need to run git rev-parse first!
if err := EnsureValidGitRepository(ctx, repoPath); err != nil {
return nil, err
}
repo := &Repository{
Path: repoPath,
tagCache: newObjectCache(),
Ctx: ctx,
}
repo.batchWriter, repo.batchReader, repo.batchCancel = CatFileBatch(ctx, repoPath)
repo.checkWriter, repo.checkReader, repo.checkCancel = CatFileBatchCheck(ctx, repoPath)
repo.objectFormat, err = repo.GetObjectFormat()
if err != nil {
return nil, err
}
return repo, nil
}
// CatFileBatch obtains a CatFileBatch for this repository
func (repo *Repository) CatFileBatch(ctx context.Context) (WriteCloserError, *bufio.Reader, func()) {
if repo.batchCancel == nil || repo.batchInUse {
log.Debug("Opening temporary cat file batch for: %s", repo.Path)
return CatFileBatch(ctx, repo.Path)
}
repo.batchInUse = true
return repo.batchWriter, repo.batchReader, func() {
repo.batchInUse = false
}
}
// CatFileBatchCheck obtains a CatFileBatchCheck for this repository
func (repo *Repository) CatFileBatchCheck(ctx context.Context) (WriteCloserError, *bufio.Reader, func()) {
if repo.checkCancel == nil || repo.checkInUse {
log.Debug("Opening temporary cat file batch-check for: %s", repo.Path)
return CatFileBatchCheck(ctx, repo.Path)
}
repo.checkInUse = true
return repo.checkWriter, repo.checkReader, func() {
repo.checkInUse = false
}
}
func (repo *Repository) Close() (err error) {
if repo == nil {
return nil
}
if repo.batchCancel != nil {
repo.batchCancel()
repo.batchReader = nil
repo.batchWriter = nil
repo.batchCancel = nil
repo.batchInUse = false
}
if repo.checkCancel != nil {
repo.checkCancel()
repo.checkCancel = nil
repo.checkReader = nil
repo.checkWriter = nil
repo.checkInUse = false
}
repo.LastCommitCache = nil
repo.tagCache = nil
return err
}